1. Field of the Invention
The present invention relates to a vibration sensor for a musical instrument and a pickup saddle.
Priority is claimed on Japanese Patent Application No. 2011-65215, filed Mar. 24, 2011, the content of which is incorporated herein by reference.
2. Description of Related Art
In the past, a pickup saddle was known which includes a vibration sensor converting a string vibration of a guitar or the like into an electrical signal and which supports a string (for example, see PCT International Publication No. WO2008/117483A1). Compared with a case where a vibration sensor is interposed between a saddle and an instrument body, it is possible to stably convert a string vibration into an electrical signal without damaging the appearance of a musical instrument by building the vibration sensor in the saddle. The vibration sensor of the pickup saddle described in PCT International Publication No. WO2008/117483A1 is bonded to an outer shell member constituting the profile of the pickup saddle with an adhesive in a state where a piezoelectric element is interposed between two electrode plates and the resultant is wound with a thread and temporarily fixed. PCT International Publication No. WO2008/117483A1 discloses a technique of bonding or applying an insulating shield material to the surface of the vibration sensor before the vibration sensor is bonded to the outer shell member so as to shield the vibration sensor from electromagnetic waves which causes noise in the output of the vibration sensor.
However, as described in PCT International Publication No. WO2008/117483A1, when the vibration sensor is bonded to the outer shell member in the state where the piezoelectric element and the electrode plates are wound with a thread and temporarily fixed, there is a high possibility that the electrical connection between the piezoelectric element and the electrode plates may be unstable. Particularly, the possibility that the contact state between the piezoelectric element and the electrode plates can vary due to a large force acting during musical performance is very high. When a conductive material such as a conductive adhesive is interposed between the piezoelectric element and the electrode plates so as to prevent the variation in contact state, the flowing conductive material may short-circuit two electrode plates with the piezoelectric element interposed therebetween.
As described in PCT International Publication No. WO2008/117483A1, the manufacturing method including the fixing of the electrode plates and the bonding and application of an insulating shield material includes many processes requiring manual work and thus raises the manufacturing cost thereof.